The ecological determinants of adaptive diversity in macroevolutionary radiations

进化生物学中一个悬而未决的主要问题是，经常在很短的时间间隔内发生变化的生态条件是如何导致数百万年稳定的进化模式的。这个问题很难解决，因为不可能对发生在宏观进化时间尺度上的过程进行控制实验。在我的研究中，我将通过对自然宏观进化实验的仔细调查来克服这个问题：在岛屿和大陆栖息地复制热带蜥蜴的进化辐射。在数千万年的时间里，在相似和不同的生态环境中，变色蜥蜴（Anolis属）独立地多样化了许多次。通过将每一种辐射视为宏观进化实验中的个体复制，我能够测试关于生态如何塑造大规模生物多样性进化的各种假设。

A major unanswered question in evolutionary biology is how ecological conditions, which often change over very short time intervals, can result in evolutionary patterns that are stable for millions of years. This question is difficult to address because it is not possible to conduct controlled experiments on processes that occur over macroevolutionary timescales. In my research, I will overcome this problem through careful investigation of a natural macroevolutionary experiment: replicated evolutionary radiations of tropical lizards in both island and mainland habitats. Anole lizards (genus Anolis) have independently diversified many times over tens of millions of years in both similar and different ecological settings. By treating each of these radiations as an individual replicate in a grand macroevolutionary experiment, I am able to test a wide variety of hypotheses about how ecology shapes the evolution of large-scale biodiversity. For this work, my first objective will be to use genetic tools to reconstruct the phylogeny (i.e., the relationships and evolutionary history) of all ~400 species of anoles. My lab will then use this historical framework to test whether competing models of the macroevolutionary process can explain the resulting diversity of body forms that we observe in these lizards today. We will next focus on identifying the proximate factors that most influence macroevolution. Specifically, we will again use a phylogenetic framework to compare the relative importance of the geographic landscape versus the ecological community for generating adaptive diversity in organisms. For our final objective, we will investigate how the transport of exotic species by humans has altered fundamental diversity patterns in anoles, and we will seek to predict how, as a result of human activities, the future determinants of diversity will differ from those of the past. The goal of this research is to advance our understanding of ecology and evolution by addressing a longstanding, unanswered question in evolutionary theory. This project will also have applied benefits for biodiversity conservation. Our work on introduced species will provide a general predictive framework for identifying trade-associated threats to species, and will be of value to stewards of biodiversity in Canada and worldwide.